Although 511 Impregnator, Porous Plus and Grout Sealer are solvents, they are only a 1 on the toxicity level (0 - 4). that is equal to laundry detergent. None of these products are considered flammable. They are all combustible (more then a 100-degree flashpoint). They are solvents so you don't want to drink them or lock yourself in a small room and start sniffing the bottle. 511 is USDA approved for used in food prep areas.
511 H2O Plus is a O on the toxicity scale, is non-flammable and has no odor. For any area where smell or allergy is a concern the customer may use 511 H2O Plus.